Control units are usually mounted in elevator cages and/or in front of shaft doors in elevator installations. Such control units serve for, for example, the input of a destination story by the passenger and for the indication of items of information, such as, for example, a designation of a story at which the elevator cage is currently located. In that case, the control units are usually connected with switching and safety circuits of the elevator installation by cable connections. At the time of service operations at the elevator installation it can be necessary to open a control unit in order to gain access to the interior of the control unit.
Generally, such control units are merely hooked in place or screw-connected. Control units which are hooked in place are often readily accessible to persons not intended to have access. Screw-connected control units generally are awkward to open.
However, in order to provide protection against vandalism, such control units are sometimes locked. Simple locks such as, for example, triangular locks sometimes do not offer effective protection against vandalism. Other locks are sometimes expensive on the one hand, and on the other hand are similarly exposed to vandalism. Thus, for example, the keyhole can be locked or damaged.